Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:    3GPP third generation partnership project    UTRAN universal terrestrial radio access network    EUTRAN evolved UTRAN    OFDM orthogonal frequency division multiplex    Node-B base station    eNB EUTRAN Node B    C-RNTI cell-specific radio network temporary identifier    T-C-RNTI temporary cell-specific radio network temporary identifier    S-Node-B source node B    T-Node-B target node B    TDD time division duplex    FDD frequency division duplex    TA timing advance    UE user equipment    SC-FDMA single carrier, frequency division multiple access    LTE long term evolution    UL uplink (UE to Node-B)    DL downlink (Node-B to UE)    HO handover    LCR low chip rate    LCR-TDD LCR-time division duplex    RU resource unit    RACH random access channel    MAC medium access control    SCH shared channel
A proposed communication system known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as E-UTRA) is under discussion within the 3 GPP. A working assumption is that the DL access technique will be OFDM, and the UL access technique will be SC-FDMA.
A random access procedure has been discussed for the E-UTRA system. For example, according to R1-061651, 3GPP TR25.814, V1.5.0, the random access procedure includes synchronized random access and non-synchronized random access. The non-synchronized random access procedure would be mainly used when the UL has not been synchronized, or after synchronization between the UE and the Node-B has been lost. This applies to both initial access and HO.
As is stated in Section 9.1.2.1.1.3 of 3GPP TR25.814, “Non-synchronized random access procedure”, prior to attempting a non-synchronized random access, the UE shall synchronize to the downlink transmission.
Two approaches for the random access procedure are considered.
Approach #1: FIG. 9.1.2.1.1.3-1 (shown herein as FIG. 1A) outlines this approach, where the Node B responds to the non-synchronized random access attempt with timing information to adjust the uplink transmission timing and an assignment of uplink resources to be used for transmission of data or control signaling (possibly including any message payload (e.g. UE ID) not included in the preamble) using the shared data channel. It may be noted that the timing information can also be combined with the uplink data resource allocation. Furthermore, the uplink data resource allocation may be implicitly indicated by associating a reserved time frequency region with a preamble sequence.
Approach #2: FIG. 9.1.2.1.1.3-2 (shown herein as FIG. 1B) outlines this approach, where the Node B responds to the non-synchronized random access attempt preamble with timing information and resource allocation for transmission of scheduling request (and possibly any additional control signaling or data). The UE then sends the scheduling request at the assigned time-frequency resource using the shared data channel or physical random access channel (for co-existing LCR-TDD based frame structure). The Node B adjusts the resource allocation according to the scheduling request from the UE.
Reference may also be had to R1-061901, Non-synchronized random access procedure, 27-30 Jun. 2006, Nokia, and to R1-061893, Preamble-based shared channel ID assignment during initial access, 27-30 Jun. 2006, IPWireless, for describing proposed non-synchronized random access procedures.